1. Field of the Invention
The present invention relates to the technical field of a bearing lubricating device, and more particularly to an oil lubricating device for a rolling bearing which rotates at high speed.
2. Description of the Related Art
A rolling bearing which is used in a portion which rotates at high speed such as a main shaft of a machine tool is lubricated with oil. Grease is easy to handle, but since the grease is inappropriate in terms of its service life, the rolling bearing is lubricated with oil. In this lubrication with oil, it is required that the lubricating oil be supplied by an appropriate predetermined amount. Since this amount is very small, it is necessary to feed the lubricating oil reliably to raceway surfaces of the bearing. As a means for feeding the lubricating oil to the raceway surfaces, air which is jetted from a nozzle or nozzles has been used. Conventionally, the lubricating oil and the air are fed by the same pipe or separate pipes each formed in the shape of a nozzle. In either case, however, such pipes are disposed in such a manner as to be oriented toward the inner space of the bearing at one location or a number of locations in the circumferential direction of the bearing.
The plurality of rolling elements of the rolling bearing are arranged at intervals in the circumferential direction by means of a retainer, and are adapted to revolve and travel on the raceway surfaces of the race rings as the bearing rotates. In addition, the air which is directed toward the inner space of the bearing for feeding the lubricating oil is jet-like high-speed air which is jetted out from the pipe at one location or the pipes at a number of locations in the circumferential direction as described above, and is intermittently interrupted by the aforementioned rolling elements which revolve and travel. Consequently, the rolling bearing issues high-frequency noise and harms the working environment of the machine tool.